The field of the invention relates generally to gas turbine engines, and more particularly, to cooling combustor components.
At least some known gas turbine engines include a forward fan, a core engine, and a power turbine. The core engine includes at least one compressor that provides pressurized air to a combustor wherein the air is mixed with fuel and ignited for use in generating hot combustion gases. Generated combustion gases flow downstream to one or more turbines that extract energy from the gas to power the compressor and provide useful work, such as powering an aircraft. A turbine section may include a stationary turbine nozzle positioned at the outlet of the combustor for channeling combustion gases into a turbine rotor downstream thereof. At least some known turbine rotors include a plurality of circumferentially-spaced turbine blades that extend radially outward from a rotor disk that rotates about a centerline axis of the engine.
In at least some known combustors, fuel and air are pre-mixed in the fuel nozzle to produce a lean burning flame that reduces NOx emissions. In some known systems, emissions are further reduced with the use of an airflow system that channels air through swirl vane assemblies and around nested fuel nozzles to reduce internal temperatures. In such systems, a fuel nozzle centerbody channels the air/fuel mixture to the ignition zone for combustion. However, the use of fuel nozzle centerbodies also undesirably increases the potential for auto-ignition, flashback, or detonation of residual fuel that lingers in areas around the centerbody. More specifically, without adequate cooling of the centerbody structure, the potential of auto-ignition, flashback, or detonation for centerbody walls to over-heat and experience burn-through, or heating of the centerbody structure that may cause local hot-spots that weaken the centerbody walls over time is increased.